Dunmer.
Slightly more exotic/unique race than Imperial, Nord and such and, most importantly, itīs the most well rounded race stat-wise, which fits my usual jack-of-all-trades adventurer "class" (I always try to play in manners which donīt lead to such a character becoming master-of-all-trades, eh).
In a more distant past I played mages whenever I could, so my first Morrowind game was with a Breton, but nowadays my favored archetype is bard, so Dunmer it is.